Due to its voluminous size, multimedia data (e.g., high-resolution images, video, high-definition TV) is extremely demanding of bandwidth resources. Thus, there is a critical need to compress multimedia data to facilitate delivery over bandwidth-constrained transmission mediums. Currently, there are various mechanisms that implement media compression.
In particular, there are there are several commercial standards for image and video compression, including JPEG, JPEG-2000, and JPEG-LS for image compression, and MPEG-1,2,4, and H.26x family of standards for video compression. Both lossless (e.g., JPEG-LS) and lossy (e.g., JPEG, MPEG) are covered under these standards.
When transmitting multimedia data over noisy transmission mediums such as wireless networks, there is often a need for both compression (to satisfy the bandwidth constraints) and robustness (to overcome the noisy transmission medium). The latter is classically accomplished through the use of forward error correction (FEC) methods (such as Reed-Solomon codes, turbo codes, LDPC codes, etc.) and/or through retransmission of lost packets in case there is (as in TCP/IP networks). Retransmission schemes ensure reliability. However, retransmission occurs at the cost of delays and buffering requirements at both transmitter and receiver, which may be prohibitive or even unacceptable in many applications.
Even if compression is not employed, optimizing the transmission delivery for the delivery of video formats is critical for achieving superior performance, but this is not included in existing source and channel coding technology.
Thus, conventional mechanisms in the field of media transmission over wireless networks involve a separation of the tasks of source coding (using state-of-the-art compression technology like H.264 and MPEG-2), channel coding (using state-of-the-art methods like LDPC and turbo codes), or retransmitting lost data in the presence of channel feedback. Such schemes are not a good fit for low-complexity and low-latency applications.